Unless otherwise indicated herein, the information described in this section is not itself prior art to the claims and is not admitted to be prior art by inclusion in this section.
In a wireless communication system, a base station provides one or more coverage areas, such as cells or sectors, in which the base station may serve user equipment devices (UEs), such as cell phones, wirelessly-equipped personal computers or tablets, tracking devices, embedded wireless communication modules, or other devices equipped with wireless communication functionality (whether or not actually “user” operated). Further, the base station may be in communication with network infrastructure including a gateway system that provides connectivity with a transport network such as the Internet for instance. With this arrangement, a UE within coverage of the base station may engage in air interface communication with the base station, and may thereby communicate via the base station and gateway system with various other entities.
In general, a base station may provide service in accordance with a particular air interface protocol or radio access technology, examples of which include Orthogonal Frequency Division Multiple Access (OFDMA (e.g., Long Term Evolution (LTE) or Wireless Interoperability for Microwave Access (WiMAX)), Code Division Multiple Access (CDMA) (e.g., 1×RTT and 1×EV-DO), and Global System for Mobile Communications (GSM), IEEE 802.11 (WiFi), and others now known or later developed.
In accordance with the air interface protocol, each coverage area provided by the base station may operate on one or more radio frequency channels each spanning a range of frequency spectrum, and the air interface may be divided over time into a continuum of transmission time units, such as frames, subframes, timeslots, symbol durations, and the like, in which communications may pass on a downlink from the base station to the UEs and on an uplink from the UEs to the base station using a designated modulated and encoding scheme. Such carriers may be frequency division duplex (FDD), in which the downlink and uplink channels are defined as separate respective ranges of frequency, or time division duplex (TDD), in which the downlink and uplink channels are defined on a common range of frequency but distinguished through time division multiplexing. Further, the downlink and uplink channels may then define various sub-channels for carrying particular communications, such a control signaling and data (e.g., user communications or other application layer data) between the base station and served UEs.
As UEs enter into coverage of the base station, the base station may become configured with connections to serve those UEs. For instance, for each such UE entering coverage on a particular carrier, the base station may engage in signaling with the network infrastructure to establish a bearer connection for carrying data between the gateway system and the base station, and the base station may work with the UE to establish a radio-link-layer connection for carrying data over the air between the base station and the UE on the carrier. Once so configured, the base station may then serve the UEs. For instance, when data arrives over the transport network for transmission to a UE, the gateway system may transmit the data over the UE's bearer connection to the base station, and the base station may then transmit the data over the UE's radio-link-layer connection to the UE.
In such a system, the base station may manage the transmission of data on the downlink and uplink in the defined transmission time units and in particular resources, such as particular subcarriers, defined in those transmission time units. For instance, as the base station receives data destined to particular UEs, the base station may schedule downlink transmission of that data to occur in particular transmission time units and may transmit the data over the air to the UEs in the scheduled transmission time units. Similarly, as UEs have data to send to the base station, the UEs may send scheduling requests to the base station, the base station may then schedule uplink transmission of that data to occur in particular transmission time units, and the UEs may then transmit the data over the air to the base station in the scheduled transmission time units.
Further, since the wireless communication system has a limited amount of resources to assign (e.g., a limited number of air interface resources per unit time available for allocation), the system may determine a scheduling priority for assigning these resources to the various UEs. In particular, for each UE operating in the wireless communication system, the system may assign a scheduling priority level for resource allocation from the system. For instance, the system may give UEs equal scheduling priority levels for resource assignment from the wireless communication system. Alternatively, the system may give some UEs higher or lower scheduling priority levels for resource assignment from the wireless communication system than other UEs.